A fixed-position package dimensioner is used to measure the X, Y and Z dimensions of an object such as a package. To provide accuracy, such a dimensioner assumes a static relationship between a camera and a plane upon which objects such as parcels are placed. Once this relationship is established, translation or rotation of the camera will usually lead to under/over estimates of a parcel's size. Likewise, the reference plane (e.g., a scale or platform) against which the dimensioner measures packages cannot usually move without introducing error. In other words, the sensors and reference plane should not move relative to each other after initialization. Independent movement of parts within the system can lead to poor accuracy of measurements of packages in all dimensions.
If a user intentionally moves the sensors to change the view of the scene, for example, previous knowledge about the reference plane becomes invalid. The user may not even be aware that changing a sensor's pose will invalidate the original setup and reduce measuring accuracy.
The user may also be unaware that the dimensioning system hardware has moved. Movement could be very gradual over time, due to, for example, a loose mounting bracket and vibration or jarring. A sensor on a wire or pole could slide slightly over time or be accidently bumped out of position.
Therefore, a need exists for an automated process of re-discovering a reference plane when initial alignment has been disturbed.